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PEP_PPM_PERF_CONSTRAINTS structure (pep_x.h)

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The PEP_PPM_PERF_CONSTRAINTS structure describes the performance limits to apply to the processor.

Syntax

typedef struct _PEP_PPM_QUERY_PERF_CONSTRAINTS {
  [out] ULONG GuaranteedPerformanceLimit;
  [out] ULONG LimitReasons;
} PEP_PPM_PERF_CONSTRAINTS, *PPEP_PPM_PERF_CONSTRAINTS;

Members

[out] GuaranteedPerformanceLimit

The guaranteed performance threshold in platform-specific units. If nonzero, this value specifies the maximum sustained performance level of the processor, taking into account all known external constraints (power budgeting, thermal constraints, power source, and so on). All processors are expected to be able to simultaneously sustain their guaranteed performance levels. For more information, see Platform Performance Thresholds.

[out] LimitReasons

The reasons for which the processor's performance can be limited. Set this member to zero or to the bitwise-OR of one or more of the following values:

Limit reason Meaning
PERFORMANCE_LIMIT_THERMAL
0x1
 The processor performance can be limited due to an out-of-band (that is, non-ACPI Thermal Zone) thermal condition.
PERFORMANCE_LIMIT_POWER
0x2
 The processor performance can be limited to keep power consumption of the processor within hardware safety limits.
PERFORMANCE_LIMIT_DOMAIN_DEPENDENCY
0x4
 The processor performance can be limited because of a voltage or frequency dependency between this processor and another, non-processor device.

Remarks

This structure is used by the PEP_NOTIFY_PPM_PERF_CONSTRAINTS notification. The GuaranteedPerformanceLimit and LimitReasons members contain output values that the platform extension plug-in (PEP) writes to the structure in response to this notification.

The GuaranteedPerformanceLimit member value is specified in platform-specific units. For example, a hardware platform might use a metric such as the processor clock frequency to provide a rough approximation to the amount of processing work that is being done.

Requirements

Requirement Value
Minimum supported client Supported starting with Windows 10.
Header pep_x.h (include Pep_x.h)

See also

PEP_NOTIFY_PPM_PERF_CONSTRAINTS